Volume-outcome relationship in transcatheter aortic valve implantations in Germany

Objectives We examine the volume–outcome relationship in isolated transcatheter aortic valve implantations (TAVI). Our interest was whether the volume–outcome relationship for TAVI exists on the centre level, whether it occurs equally for different outcomes and how it develops over time.


Design Secondary data analysis of electronic health records. The comprehensive

German Federal Bureau of Statistics Diagnosis Related Groups database was

queried for data on all isolated TAVI procedures performed in Germany between

2008 and 2014. [...]


Results Between 2008 and 2014, a total of 43 996 TAVI procedures were performed

in 113 different centres in Germany with a total of 2532 cases of in-hospital

mortality. Risk-adjusted in-hospital mortality decreases over the years and is

lower the higher the annual procedure volume at the centre is. The magnitude of

the latter effect declines over the observation period. Our results indicate a

ceiling effect in the volume–outcome relationship: the volume–outcome

relationship is eminent in circumstances of relatively unfavourable outcomes.

Alongside improving outcomes, however, the volume–outcome relationship

decreases. Also, a volume–outcome relationship seems to be absent in

circumstances of constantly low event rates.


Conclusions The hypothesised volume–outcome relationship for TAVI exists but

diminishes and may disappear over time. This should be taken into account when

considering mandatory minimum thresholds.



Volume-outcome relationship in transcatheter aortic valve implantations in Germany 2008-2014: a secondary data analysis of electronic health records (British Medical Journal).


DOI: 10.1136/bmjopen-2017-020204